This invention refers to an apparatus for simultaneously welding and cutting soft film and fabric material by ultrasonic energy. Welding and cutting of thermoplastic fabric material by ultrasonics has been shown for instance in U.S. Pat. No. 3,378,429 dated Apr. 16, 1968 entitled "Method and Apparatus for Treating Material with Sonic Energy" issued to E. B. Obeda, in Japanese Pat. No. 250,121 dated Mar. 6, 1959, or in the article "Ultraschallverfahren zum Verbinden und Trennen von Kunststoffen", by E. A. and R. E. Nier, published in Zeitschrift fur Schweisstechnik dated January 1965, pages 12 through 19.
In these arrangements a horn, resonating at an ultrasonic frequency, is brought into forced contact with one side of sheet material made entirely or partially of thermoplastic material, while the other side of the material is supported on an anvil surface. The transfer of vibratory energy from the horn to the material provides a weld and a suitably shaped cutting surface of the horn, upon impact on the material and anvil surface causes a cut in the sheet material. In this manner, as has been shown in the art referenced, it is possible to simultaneously weld and cut thermoplastic material while providing a finished edge at the cut.
Several problems, however, are manifest with an arrangement of this type. Most significantly, the high frequency repetitive impact of the knife edge of the horn upon the anvil surface causes a rapid wear of the cutting surface and already after a few hours of operation, either the knife edge of the horn or the anvil surface must be reworked. This condition is quite apparent considering that in an ultrasonic apparatus the repetitive impact of the horn surface upon the anvil occurs at a frequency of 16 kHz or higher, and that the force of impact is several thousand g. Also the contact between the horn frontal surface and the anvil results in audible chatter.
There exists a need for fabricating various articles from thermoplastic material or textile material having thermoplastic constituents by the use of ultrasonic energy as is shown, for instance, in the U.S. Pat. No. 3,562,041 dated Feb. 9, 1971 "Method and Apparatus for the Ultrasonic Joining of Materials According to a Pattern" issued to C. A. Robertson, which patent reveals the manufacture of shirt sleeve cuffs. Two sheet-like elements are fed underneath an ultrasonically vibrated horn while being supported on a contoured anvil which is provided with the raised outline of a cuff or some other desired pattern. After the sealed material portion leaves the welding station, a separate cutting device is used to sever the sealed or welded material portion from the surrounding web. Sealing or welding of thermoplastic sheet material is shown also in U.S. Pat. No. 3,733,238 dated May 15, 1973 "Apparatus for Vibration Welding of Sheet Material" issued to D. D. Long et al., without that any cutting or severing means are used.